Composition of hard lead alloys.



FEE.

FRANCIS C. FBARY, OF MINNEAPOLIS, AND STERLING N. TEMPLE, OF ST. PAUL, MINNESOTA; SAID TEMPLE ASSIGNOR OF ONE-SIXTH OF THE WHOLE RIGHT TO SAID FRARY.

COMPOSITION OF HARD LEAD ALLOYS.

No Drawing.

To all whom it may concern Be it known that we, FRANCIS C. FRARY and STERLING N. TEMPLE, citizens of the United States, and residents, respectively, of Minneapolis, in the county of Hennepin and State of Minnesota, and St. Paul, in the county of Ramsey and State of Minnesota, have invented new and useful Improvements in the Composition of Hard Lead Alloys, of which the following is a specification.

Our invention has for its object to provide an improved metallic alloy having certain characteristics especially adapting it for use in the casting of type and similar articles in molds, and in the manufacture of bullets and other forms of ammunition.

In the manufacture of type metal, hardness and resistance to compression without cracking are necessary, and furthermore, the metal employed must be of such a character that it will not contract on solidifying, but,

on the contrary, will slightly expand and fill the mold in which it is cast. In the manufacture of ammunition, it is very desirable that the alloy be hard and that its specific gravity be as high as possible, so as to thereby concentrate the maximum of kinetic energy in a minimum volume.

Certain of the above noted desirable characteristics have hitherto been produced by adding a considerable proportion of anti; mony to lead. The antimony, however, re duces appreciably the specific gravity of the alloy. Furthermore antimony, at the present time, is very expensive as compared with lead, and because of the considerable amount thereof necessarily employed, makes the alloy expensive.

In carrying out our invention, We use metallic barium, alloyed with a main body of lead. \Ve have found that, weight for weight, the hardening efiect of barium is much greater than that of antimony, and that only a small amount of barium is necessary to produce a hard alloy of commercial value. We have also found that the alloy containing a small amount of barium may be improved by the addition of a small amount of copper. This causes the alloy to be tougher and finer grained, and prevents it from having that brittleness which characterizes ordinary antimonial lead and alloys containing lead and barium alone.

As examples of alloys made in accordance Specification of Letters Patent.

" Patented Nov. 2

Application filed August 13, 1915. Serial IN 0. 45,378.

with our invention, we give the following three formulae: 1. Ninety-four parts lead and six parts barium. 2. Ninety-four parts lead, six parts barium, and two-tenths of a part of copper. 3. Ninety-seven parts lead, three parts barium, and one-fourth of a part of copper. The first two of these alloys above-mentioned are harder than commercial antimonial lead, while the third is of about the same hardness as antimonial lead. The first is rather coarsely crystalline in fracture, and about as brittle as antimonial lead, while the second has a rather fine crystalline fracture, and is tough. The third is of finer structure and tougher than the second, but not quite as hard.

What we claim is:

1. As a new article of manufacture, a hard lead alloy, suitable to the uses commonly made of such alloys, containing lead and barium.

2. As a new article of manufacture, a hard metallic alloy, having a main body of lead and containing a small amount of metallic barium.

3. As a new article of manufacture, ahard metallic alloy having a main body of lead and containing a small amount of metallic barium and also a small amount of metallic copper.

4. As a new article of manufacture, a hard lead alloy having a main body of lead and containing metallic barium in an amount less than ten per cent.

5. As a new article of manufacture, ahard metallic alloy having a main body of lead and containing metallic barium in an amount less than ten per cent., and a small amount of metallic copper.

6. As a new article of manufacture, a metallic alloy containing lead, barium and copper. e

Signed at Minneapolis, Minn, this 5th day of August, 1915.

FRANCIS C. FRARY.

Witnesses:

ALICE W. FRARY, W. KRITCHEVSKY. Signed at Morristown, Minn, this 10th day of August, 1915. 

